Generally, semiconductor devices are used in a variety of electronic applications, such as computers, cellular phones, personal computing devices, and many other applications. Home, industrial, and automotive devices that in the past comprised only mechanical components now have electronic parts that require semiconductor devices, for example.
Semiconductor devices are manufactured by depositing many different types of material layers over a semiconductor workpiece, wafer, or substrate, and patterning the various material layers using lithography. The material layers typically comprise thin films of conductive, semiconductive, and insulating materials that are patterned and etched using lithography to form integrated circuits (ICs). There may be a plurality of transistors, memory devices, switches, conductive lines, diodes, capacitors, logic circuits, and other electronic components formed on a single die or chip, for example.
Lithography is a process in which a layer of photosensitive material is deposited over a material layer, and the layer of photosensitive material is patterned by exposing the layer of photosensitive material to energy through a lithography mask. The layer of photosensitive material is then developed, and the layer of photosensitive material is used as a mask while exposed portions of the material layer are etched away.
Dry etch techniques such as physical sputtering, ion beam milling, reactive ion etch (RIE), and plasma etch processes are often used to pattern material layers of semiconductor devices, for example. However, some material layers in semiconductor devices, such as nitride layers, as an example, are often etched or removed using wet etch processes.
In a wet etch process, typically a semiconductor wafer or batch of semiconductor wafers are submerged in an etching liquid during an etch process. However, in some applications and with some wet etch chemistries, it can be difficult to control the etch rate.
Thus, what are needed in the art are improved wet etch processes and processing systems.